Dual resonant jet propulsion engine for aircraft



Sept. 26, 1950 P. H. KEMMER ETAL DUAL RESONANT JET PROPULSION ENGINE FOR AIRCRAFT Filed Nov. 9, 1945 4 Sheets-Sheet 1 Sept. 26, 1950 P. H. KEMMER ET AL 2,523,308

DUAL RESONANT JET PROPULSION ENGINE FOR AIRCRAFT Filed Nov. 9, 1945 4 Sheets-Sheet 2 Sept. 26, 1950 P. H. KEMMER ET AL DUAL REONANT JET PROPULSION ENGINE FOR AIRCRAFT 4 Sheets-Sheet 3 Filed Nov. 9, 1945 due;

Sept. 26, 1950 P. H. KEMMER ETAL DUAL RESONANT JET PROPULSION ENGINE FOR AIRCRAFT 4 Sheets-Sheet 4 Filed NOV. 9, 1945 Q 4 j 2%. H 4m 7 y; z r M? 6 3 SQ y d J T n Q Z T l|| NM W m M\ N l %N w\ Patented Sept. 26, 1950 DUAL RESONANT JET PROPULSION ENGINE FOR AIRCRAFT Paul H. Kemmer, Fairiield; and Herbert M. Heuver and Frank L. Wattendorf, Dayton, Ohio Application November 9, 1945, Serial No. 627,771

8 Claims. (o1. 60-355) (Granted under the act of March-3, 1883, as

The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to us of any royalty thereon.

This invention relates to jet propulsion motors and more particularly. to dual jet propulsion engines for aircraft, having for one of its objects the provision of two or more jet propulsion units of the intermittent or resonant type having sideby-side, parallel jet reaction tubes connected together to discharge alternately from one tube to the other in synchronized relation, utilizing a [portion of the discharge impulses from each combustion chamber and reaction tube to compress and fire the explosive mixture in the other combustion chamber.

A further object of the invention is the provision of a plurality of jet reaction tubes for a jet propulsion engine, shaped to form acoustical resonant spaces connected together to form shock wave conducting means within the spaces, causing cyclic pressure impulses of suction, compression, combustion and exhaust to occur alternately in the spaces, effecting a continuous and uniform thrust from the engine.

A further object is the provision of a plurality of resonant jet propulsion units constituting a jet propulsion engine in which the resonant cycle of fuel charging, compression, combustion and discharge of each unit is controlled by the cyclic operation of one of the other units to provide a substantially uniform thrust jet propulsion engine.

A still further object is the provision of a plurality of jet propulsion units constituting a jet propulsion engine utilizing the shock wave from each of the jet units, following the cyclic combustion in that unit. for compressing and firing the combustible mixture in another of the jet units. A

A still further object is the provision of a dual jet propulsion unit having improved fuel supplying and pumping means for alternately supplying fuel to the jet units. in which the combustion pressure and shock wave in each of the units during the combustion therein constitutes pressure means for actuating the fuel supplying and pumping means to supply fuel to the other jet propulsion unit of the engine.

A still further object is the provision of a dual amended April 30, 1928; 370 0. G. 757) Another object is the utilization of pressure operated means for varying the operation of the fuel supply means for a plurality of jet propulsion units, constituting a jet propulsion engine, in proportion to variations in the atmospheric pressure of the air surrounding the units.

A further object is the provision of a plurality of jet propulsion units constituting a jet propulsion engine, having means for causing the jet propulsion units to operate alternately, or convices from an alternate operation to a continuous operation.

A further object is the provision of a jet propulsion engine having a jet propulsion unit with an athodyd form of surrounding casing, constituting supplemental propulsion means for the engine, utilizing the heat from the main reaction propulsion unit to supplyheat to the air passing through t e athodyd casing to effect the air expansion wit the athodyd and the high velocity air discharge from the athodyd, supplying supplemental thrust to the engine.

Like reference characters refer to like parts in the several figures of the drawings in which:

Fig. 1 is a somewhat diagrammatic horizontal longitudinal sectional view through our improved dual jet propulsion engine.

Fig. 2 is a vertical sectional view taken approximately on the plane indicated by the line 2-2 of Fig. 1.

Fig. 3 is an end view of the front end of the engine illustrated in Figs. 1 and 2, somewhat diagrammatically illustrating the arrangement of the air admission tubes and the intermediate fuel spray jets. I

Fig. 4 is a cross-sectional view taken through one of the dual jet propulsion units, on the plane indicated by line 4-4 of Fig. 2, illustrating the athodyd casing and the cooling fins between the same and the reaction jet tubes.

Fig. 5. is an enlarged detail sectional view through one of the valved air-admission tubes.

Fig. 6 is an enlarged vertical cross-sectional view takenthrough one form of our improved fuel supply control means, illustrating the heads of the jet reaction tubes, and in full lines, the fuel delivery conduits and headers andspray nozzles forsupplying fuel under. pressure to the Fig. 8 isa horizontal longitudinal sectional view illustrating a modified form of dual jet propulsion engine,

Fig. 9 is a front elevation of the modified form of dual jet engine illustrated in'Fig. 8.

' Referring more particularly to Figs. 1, 2 and 3 of the drawings, our improved jet propulsion engine includes a pair of side-by-side jet propulsion units or tubes as indicated at I and 2,-disposed in parallel relation to each other. The propulsion units comprise enlarged spherical head members orcombustion chambers 3 and 4, having reduced streamlined rearwardly extending discharge ports connected to rearwardly and outwardlydiverging jet discharge tubes 5 and 5, terminating in discharge ports or openings 1 and 8.

A conduit 9, of a substantial diameter, approximately equal to the diameter of the forward end of the jet discharge tube 5 or 6, connects these two jet discharge tubes together. The conduit 3 is preferably U-shaped and is curved uniformly throughout its length with both of its ends facing forwardly in free communication with the interior of the reaction or jet discharge tubes l and 2, so as to alternately receive a portion of the jet discharge and the shock wave created thereby, from each jet tube and discharge the same into the other jet tube, conducting the jet gases and shock waves through the conduit and discharging the same in a forward direction, into the other jet discharge tubes at the other end of the conduit, for purposes later to be described.

Surrounding the primary jet discharge tubes 5 and 6, and a portion of the spherical combustion chambers 3 and 4, are a pair of communicating athodyd chambers or secondary thermal air jet thrust units l and l I, having annular air intake ports 12 and I3 at their forward ends with intermediate enlarged air heating chambers I4 and i extending rearwardly into the tubular thermal air discharge passages l1 and I3 which terminate in ring-like thermal air discharge ports l3 and 20.

Radial heat exchange fins 2| are carried by the spherical heads ,3 and 4'and jet discharge tubes 5 and 6 between the same and the inner walls of the athodyd casing'for cooling the combustion chambers 3 and 4 and the primary jet discharge tubes 5 and 6, upon the passage of air through the athodyd chamber to prevent them from reaching critical disintegrating temperatures. An exchange of heat from the throat or front end of and I are providedwith a plurality of closely and uniformly spaced air admission tubes 23, as best seen in Figs. 1, 3 and 5. These tubular members 23 extend forwardly from the combustion heads 3 and 4 in parallel relation'to each other sub-- stantially in the direction of movement of the aircraft or other mobile unit carrying the dual jet engine. I

These tubular air admission check valve members 23 are secured in suitable openings in the front portion of the spherical heads 3 and 4, each comprising a cylindrical tube 24 having a pair of thin flat spring valve members or reeds 25, 28 with their forward end portions 25' and 26 extending longitudinally acrossthe inside of the tubular members, the rear portions 25" and 26" being curved and tensioned outwardly to engage the inner circular portions of the tubular members. Air circulation ports 21 are formed in the tubular members 23 adjacent the combustion heads 3 and 4 in'opposed relation to each other in, a plane at right angles to the plane of the forward portions 25', 26' of the reed members 25 and 26. The free ends and edges of the reed members 25, 26 are formed to fit the inner surface of the tubular members and are sufliciently flexible to yield toward each other when a predetermined reduction in the pressure within the combustion chambers occurs, and by the ram pressure of the tubes 5 and 3 also takes place, heating and expanding the air passing therethrough, particu- -larly in the enlarged portions of the athodyd chambers l4 and IS. A tubular connecting shell 22 surrounds the U-shaped passage 9, connecting the two athodyd chambers together, as best seen in Fig." 1. v I

Air is introduced into the spherical combustion chambers 3 and 4 in any well-known manner, such as by leaf spring valve means commonly employed in reaction jet propulsion devices of this type employing a reaction jet pipe, wherein the inertia of the gases passing from the combustion chambers rearwardly at high velocity in the jet discharge pipe, following the combustion in the spherical combustion chambers, creates a partial vacuum in the combustion chambers causing fresh air to be drawn through the air vents in the forward or head portions of the combustion chambers through the leaf spring reeds or check valves.

For purposes of illustration, the forward areas of each of the spherical combustion chambers 3 air entering the forward ends of the tubes. The combustion pressures of the fuel being burned within the spherical combustion chambers 3 and 4 forces the reeds closed to prevent gases from escaping forwardly past the tubular reed members 25 and 28. t

Air is circulated through the air intake tubes 23 by the ram effect, when the jet engine moves forward through the' air, this air passing along the opposite sides of the reeds, and out through the openings 21, produces air circulation and cooling effect on the reed members and the tubular air intake members 23.

Referring more particularly to Figs. 1 and 3, fuel is sprayed into the spherical combustion heads, between the air intake tubes'23, at a pluraiity of uniformly spaced points, as illustrated in thedrawings, under the control of a fuel delivery control unit, later to be-described, and indicated diagrammatically at 28 in Figs. 1 and 3;

The fuel injection nozzles 23. extend-into the combustion chambers 3 and 4 and are connected to fuel delivery headers 3| (Fig. 6) and supply pipes 30 which extend across the front portions of the spherical combustion heads 3 and 4 in parallel relation to each other, each pipe 33 having spray nozzles 28 connected thereto. A common header 3| may be employed for each combustion chamber for supplying fuel to the supply pipes 30.

Conventional spark plug means 32 is disposed in at least one of the spherical combustion chambers, as indicated in Fig. 1, including suitable conventional operating means, not shown, for energizing the plug to fire the mixture in the combustible chamber 3, and start the dual jet engine into operation.

Referring now to Fig. 6, our improved fuel supply control unit as diagramamtically illustrated at 28 in Fig. 1 will now be described. The fuel supply control unit 28 is suitably carried by the jet engine, preferably between the heads 3 and 4 and the jet tubes 5 and 6, and comprises a valve casing 33 having two valve chambers 33a and 33b, connected by fuel conducing passages 35 and 36, to the headers 3|. A fuel chamber 31 is provided, having a fuel inlet passage 38, with a needle valve 39 therein, the passage 38 being connected at its other end to a fuel reservoir 48.

The valve chambers 33a and 33b are formed with valve seats 4| and 42 therein, receiving poppet valves 43 and 44 having stems 45 and 48 extending through the casing to the exterior thereof with the ends of the valve stems connected respectively to a pair of centrally pivoted levers 41 and 48, pivoted at 49 on a rigid bracket 58 depending from the valve casing 33. The longer arms 41 and 48' of the levers 41 and 48 are connected by actuating rods 52 and 53 to pressure operated bellows members 54 and 55, preferably of the Sylphon" type. These bellows members 54 and 55 are expanded by pressure supplied through conduits 58 and 51 from the spherical combustion chambers 3 and 4. When an explosion occurs in one of the combustion chambers, such as the chamber 4, the pressure therein becomes effective through the conduit 51, on the bellows 55 to rock the lever 41 clockwise to unseat the valve 43, permitting fuel from the tank 48 to flow through passage 38, chamber 31 and passage 35 into the headers 3| and through the supplemental supply pipes 38, and spray nozzles 29, in-

to the other combustion chamber 3, supplying the latter combustion chamber with fuel incident to pressure resulting from the explosion in the combustion chamber 4. Springs 58 and 59 normally close the valves 43 and 44 except when actuated by the bellows meinbers 55 and 58, and maintain the bellows members in theircollapsed conditions.

The longer lever arms 41' and 48 of the levers 41 and 48 have spring seats 88 and 8| project- 'ing therefrom, between which'is interposed a fairly stiff return spring 62 designed to be tensioned by movement of one of the levers 41 or 48 to rock the other lever 48 or 41,120 move the opposite valve to its closed position as the other lever moves its valve to open position. 1

The needle valve 39, which controls the rate of fuel flow through the passage 38 between the fuel tank 48 and the fuel chamber 31 is adjustable for a predetermined ratio between the altitude and speed of travel of the craft carrying the dual jet engine, since the proper explosive mixture of fuel and air introduced into the combustion chamber depends on the air speed or ram effect of air entering the combustion chamber and the altitude of barometric pressure of the air entering the combustion chamber.

The casing surrounding the fuel chamber 31 the opening'll, and changes the pressure within the bellows 88, adjusting the position of the upper end of the floating lever 88, and the fuel a controlling position of the needle valve 39 to accommodate this change in speed and air pressure.

Means may be provided for varying the setting or fuel air ratio adjustment of the needle valve, such as a threaded adjusting screw 16 carried by a bracket extension 11, from the bracket 83, and connectedto the upper end of the floating lever 88 by a spring 18.

While our dual jet propulsionen gine is designed to start and run by fuel introduced alternately into the combustion chambers 3 and 4, and compressed and fired by a portion of the jet discharge and the shock of the previously flred jet which is. conducted into the other jet discharge tube to compress am fire the charge in the combustion chamber, provision is also made for introducing fuel into both combustion chambers simultaneously, so that the jet units may also 'flre independently of each other.

It is assumed that high speeds, where the ram effect of the air entering the combustion chambers 3 and 4 through the air intake tubes 23 is sufficiently high, the dual jet units may be fired simultaneously or independently of each other.

carries an upstanding bracket arm 83 having a guide bearing 84 therein for receiving the shank 85 of the needle valve 39, A floating lever 58 is pivoted at 81- to the outer end of needle valve shank 85, the upper end of this lever being connected at 88 to a bellows 69 having an air intake conduit 10 leading therefrom, with an air intake opening 1| at the end thereof facing in the direction of movement of the dual jet engine through the air, when mounted on an aircraft.

The lower end of the lever 66 is connected at 12' between a closed bellows 13 carried by a bracket 14 projecting laterally from the fuel chamber casing 31, and a coil compression spring 15 seated against the upstanding bracket 83. Changes in altitude of the aircraft utilizing the jet engine varies the air pressure on the exterior of the closed bellows device 13, with the result that the spring 15 rocks the floating lever 88 in ratio to the change in bellows pressure, adjusting the position of the needle valve 39 for the relative changes in altitude. Variations in the speed of the craft and airdensity likewise varies the pres- Referring again to Fig. 6, the fuel chamber 31 is provided'with two by-pass conduits 19 and 88, each having a fuel control valve 8|, 82 of the rotary plug type therein.' These two valves 8|, 82 are normally closed; as shown in full lines, and are provided with operating arms 83 and 84 connected to each other by an operating link 85. The arm 84 has anupwardly extending latch lever portion 88, held in the position shown in full lines, against the tension of a compression spring 81, by a latch member 88, pivotally secured at 89 to the fuel chamber, on'an ear projecting from the fuel supply pipe 38, leading from the fuel tank 48.

Raising of .the latch 88 releases the valve controlling lever arm 86 and the spring 81 rotates 'bom type of jet engine. As before indicated,

means may be provided for changing the operation of our improved jet engine from the dual,

alternate firing type, to a dualjet independently firing type, when the speed of the aircraft carrymg the jet engine increases beyond a predetermined rate.

A bellows 9| is secured to the top of the fuel chamber 31, just under the latch member 88, the bellows 8! having an air inlet pipe 92 with its mouth 93 extending forwardly in the air stream in the direction of travel of the aircraft employing the jet engine. This bellows 9| may be of metallic or Sylphontype so that the inherent resiliency of the same yieldably resisting the expansion thereof regulates the amount of air pressure necessary within the bellows to raise and release the latch member 86, and consequently prevents raising of the-latch until the velocity and pressure of the air passing into its air pressure reservoir 91 for initially pressurizing the fuel in the tank for starting when air pressure at the air. intake 95 is very low.

Another typ of fuel metering unit that may be utilized is disclosed in Fig. 7 in which the fuel tank is illustrated at I00, having a fuel delivery conduit 10! with a fuel metering needle valve I24 and check valves I03 and I04 therein, connected to two bellows pumps I05 and I06. These pumps discharge through conduits I01 and I08, having check valves' I09 and there-- in, into the fuel spray nozzles III, located in the combustion chambers H2 and H3, similar to the spray nozzles 29-in the combustion heads 3 and 4 in Fig. 6. A lever H4 is centrally pivoted at II4a on a bracket II5, the lever having its ends connected to depending bifurcated projections H6 and III extending from the actuating bellows members H8 and H9 which are secured on the frame-I20, preferably between two combustion chambers II2 and H3. The conduits I2I and I22 lead respectively from the bellows members II! and H8 to the combustion chambers H3 and I I2.

Combustion within the chamber I I3, for instance, pressurizes the conduit I2I, expanding the bellows II9 which compresses the pump bellows I06 containing fuel. Expansion of the bellows II9 rocks the lever II4 counter-clockwise, raising the abutment II6 from its engagement with the fuel pump bellows I05, simultaneously forcing the abutment II'I downwardly to compress the bellows I06, forcing the fuel therein through the conduit I08 and spray nozzles III,

sure conduit I28 connected thereto with an air intake opening I28 in the end of the conduit, facing in the direction of travel of the aircraft carrying the device. The bellows I21 is biased by a spring I28, tending to stabilize theposition of the right-hand end of the floating lever I23 at various positions, depending upon the air pressure entering the intake opening I29. Variations in altitude and barometric pressure adjust the left-hand end of the floating lever I23, and the needle valve I24 is correspondingly adjusted to regulate the fuel supplied to compensate for the air pressure variations. Variations in the speed of the aircraft carrying the dual jet engine varies the ram effect of the air entering thecombustion chambers H2 and H3, and the amount of air entering the air intake I29 for the conduit I28 which causes a variation in.

in Fig. 8, and in Figs. 1 to 5, have been given the' same reference characters as inFigs. 1 to 5, and

will not'be described again in detail in this modification. The spherical combustion chambers 3 and 4 in Fig. 8 are surrounded by rearwardly tapering air collecting casings or jackets I30 and I3I,' necked down and faired into the'diseharge Jet tubes 5 and 6 as indicated at I32 and I33.

The jet discharge outlets from the combustion chambers 3 and 4 are somewhat smaller than the forward ends of the jet discharge tubes 5 and. 6 where they join the necked down ends of the jackets I30, I3 I soasto leave rearwardly extending air passages'I34 and I35 between the rearwardly extending exterior combustion outlet portions of the combustion chambers 3 and 4 and the air collection casings I30 and I3I. The combustion outlets from the chambers 3 and 4 instead of being connected directly to the reaction tubes 5 and '5, as disclosed in the first form of the invention, are each provided with a relatively 1, it will be observed that an automatic fuelinjection means is provided for introducing fuel alternately into the two jet discharge tubes to maintain-the introduction of the fuel in one combustion chamber, in timed ratio to the intro:- duction and ignition of fuel in the other combustion chamber. I

Fuel-air ratio control means is also provided in this form of the invention, somewhat similar to that disclosed in Fig. 6. A centrally pivoted floating lever I23 is provided; which carries the fuel metering needle valve I24. The lever I23 is connected at one end intermediate a closed bellows I25 and a compression spring 'I26. Variations in air pressure due to altitude adjusts the bellows I25 connected to the end of the floating lever I23. The opposite end of the'lever I23 is connected to a second bellows I21, having a presathodyd chambers I0 and I I.

A plurality of static pressure tubes I36 and I39 extend rearwardly, as shown in Fig. 8, having their forward ends disposed in communication at I40 and HI with the interior of the combustion chambers 3 and 4. The tubes I38 and I38 taper and curve rearwardly with their rear extremities connected to enlarged header members I42 and I43, having air induction ducts I44, I45

projecting into the jet discharg tubes 5 and 6, and. facing forwardly substantially in alignment with the-annular air discharge openings I32 and plied with fuel in the same manner as that disclosed in the first form as illustrated in Figs. 1 to in that chamber.

6.' At lower velocities the pressures from the explosions in the-combustion chambers 3 and 4 (Fig. 8) are transformed into dynamic pressure at the jets from the nozzles I33 and I31, when the static pressures in the jet discharge tubes 5 and 6 reach a low value, permitting air from the ducts I34 and I35, leaving the annular discharge ports I32, I33, to enter the discharge tubes 3 and 3. Since the intake nozzles I44 and I43 project into the jet discharge tubes 3 and 3, just to the rear of the annular ducts I33 and I34, they pick up the dynamic pressure of combustion leaving the combustion chambers 3 and 4, through the short discharge nozzles I33 and I3'I, 'and the air .entering the front of the casings I33 and I3I around the spherical combustion chambers and leaving through the annular discharge ports I34 and I35.

At low velocities, the ram effect at the auxiliary air ports I2 and I3 isnot sumc'ient to force air through the plural tubes I33 and I33 and into the combustion chambers 3 and 4.

As the air velocities increase, the ram effect of the air entering the air intakes I2 and I3 increases until it has a sufficient ram effect to force the air from the funnel-shaped casings I33 and I3I surrounding the combustion chambers 3 and 4, through the annular air discharge nozzles I32 and I33 into the ducts I44 and I45, and through the curved'tubes I33, I33 back into the combustion chambers 3 and 4. When velocities of this magnitude, occur, the air pressure and tinuously to the spray nozzles 23 from the pressurized fuel tank 43. Fuel is now fed continuously into the two combustion chambers 3 and 4 (Fig. 8), and air is also fed into the combustion chambers continuously, at these high velocities, by the ram efi'ect of the air entering the intake ducts I44 and I45. This operation results in a continuous operation of both of the combustion units, resulting in a continuous thrust from the propulsion engine.

Briefly summarizing the operation of the preferred form of our invention, as shown in Figs. 1' to 6, before starting the engine, both com-- bustion chambers 3 and 4 should be primed so as to contain a'combustible mixture of fuel and air. The switch is then closed to the jump spark plug in the combustion chamber 3, firing the mixture As the explosion occurs, the jet leaving thechamber and a portion thereof entering the jet discharge tube 5 at high supersonic velocity creates a high pressure shock wave and a portion of this shock wave and the pressure gases enters the curved communicating passage 9, and are conducted by the passage 3 toward the discharge opening of the other combustion chamber 4. These hot gases and the high velocity shock wave striking the combustible mixture in the combustion chamber 4 and the'forward end f of the discharge tube compress the mixture to a degree where it. is ignited from the pressure imposed. Even though the combustion chamber *through the conduit 3 toward the combustion chamber 4.

As combustion in the chamber 4 takes place, the velocity ancl inertia of the gases leaving the jet discharge tube 5 create a reduction in pres- .sure in the chamber 4, causing air to be drawn into this chamber through the air inlet tubes 23, past the yieldable spring valves or reeds 23, 23. This reaction in the jet discharge tube 5 occurs as inertia of the discharging gases is overcome when the explosion in the. other combustion chamber occurs, pres'surizing the bellows 33 through the pipe 31, to open the valve 43 and admit fuel under pressure, to pressurize the fuel line to the spray nozzles 23 in the combustion head 3. When the shock wave om the tube 3 passes along through the cond t 3 and strikes the gases in the combustion chamber 3, these gases are compressed and ignited.

From the foregoing, it will be observed that the dual jet propulsion units will fire alternately, giving a substantially continuous thrust to the engine, also by utflizing the shock wave from the combustion in each unit to assist in the compression of the combustible mixture in the other unit, this, together with the well-known reaction effect of the jet discharge will increase the efficiency of'each jet unit and the power output from the engine. 1

The efliciency of the units is also increased by the employment of the athodyd cooling chambers I3 and II, since the air that is packed into the enlarged portions I4 and I5 by the ram effect at the entrance I2 and I3 is heated at the enlarged portion, expanded and then permitted to discharge freely toward the rear at high velocity along the exterior of the jet discharge tubes to escape through the thermal air jet discharge dpenings I3 and 20.

When a suflicient relative velocity of the air passing the jet engine has been obtained, the

1 latch 83 is raised by the air pressure entering 4 should contain no fuel mixture, the pressure in as jet propulsion motors.

the inlet opening 33 (Fig. 6), permitting fuel to be fed directly from the fuel tank to the spray nozzles 23. Under these conditions, both jet units mayoperate independently of .each' other The rate of fuel flow is also regulated by the needle valve 33 to maintain a. desired fuel-air ratio for variations in the ram air pressure due to the velocity of the air entering the pipe I I and by reason of changes in discharge opening facing rearwardly, means for supplying fuel to said combustion chambers alternately or continuously, air pressure operated control means movable relatively in oppoacsaaos site directions for causing said fuel supply means to operate alternately or continuously and air supply means having an air inlet extending forwardl and connected to the air pressure operated control means for moving the same in one of its directions. ,i

2. In a dual Jet propulsion engine of the class described, a pair. of spaced parallel jet propulsion units of the intermittent reaction type, each having an enlarged combustion chamber at its forward end with one way air admission valve means therein facing forwardly for admitting air into the combustion chamber when the air pressure immediately ahead of the combustion chamber exceeds a predetermined relative pressure within the combustion chamber, a jet discharge pipe extending rearwardly from thewrear end ofthe combustion chamber and open to atmosphere at its rear end, and in communication at its forward end with the rear end of the com- 'bustion chamber, the discharge pipes of the two and adjustable fuel supply means connected between the said units, adjustable in one position to admit fuel alternately into the combustion chambers and adiustable to a second position to admit fuel continuously into both of said combustion chambers.

3. A jet propulsion engine comprising a pair of spaced side-by-side combustion chambers and jet reactiontubes leading rearwardly therefrom in parallel relation to each other each with a jet discharge opening facing rearwardly, an unrestricted communicating conduit between said jet. reaction, tubes having'its opposite ends extending forwardly in communication with the forward portions of the jet reaction tubes for receiving cyclic impulses of pressure from either combustion chamber and conveying said impulses into the other reaction tube in a direc-- tion toward the combustion chamber communieatin therewith, means for introducing air intx: said combustion chamber, and single fuel supply rect to both combustion chambers and air pres-, sure supplying means connected to said air pressure operated means having an air pressure supply opening facing forwardly for receiving air therein in proportion to the air passing said jet propulsion engine.

5. A jet propulsion engine comprising spaced parallel jet reaction propulsion units, each having an enlarged combustion chamber with air admission valve means in the forward end thereof for admitting air into the combustion cham ber incident to combustion and discharge of the gases therefrom through said Jet reaction tubes, fuel introducing means for each combusti n chamber comprising pressure operated fuel elivery means connected to the fuel introducing means for each combustion chamber having pressure operated actuator means connected to the other combustion chamber for actuating the fuel delivery means for one combustion chamber by pressure received from combustion within the other combustion chamber to alternately supply fuel to each combustion chamber, means for supplying fuel from said fuel reservoir directly and simultaneously to both of said combustion chambers for simultaneously introducing. fuel 'into both of said combustion chambers, spring closed valve means controlling said last mentioned fuelsupplying means,; and air operated means for opening said last mentioned valve means having an air inlet port facing forwardly.

6. In a dual jet propulsion engine, a pair of jet propulsion units disposed in spaced parallel side-by-side relation, each unit comprising a combustion chamber extending forwardly with a rearwardly and disposed in communication with the short jet discharge tube for that combustion .4 chamber and terminating in a rearwardly exmeans connected to both of said combustion stricted communicating conduit between said jet ,reaction tubes having its opposite ends extending forwardly in communication with the forward portions of the Jet reaction tubes for receiving cyclic impulses of pressure from. either ,combustion chamber and conveying said impulses into the other reaction tube in a direction toward the combustion chamber communicating therewith, fuel supply means for supplying fuel alternatin or continuously to said combustion chambers,v air pressure operated means for in-' terrupting the operation of said alternately operable fuel supply means and supplying fuel ditending elongated jet reaction discharge pipe, a

plurality of air collection tubes surroundingeach of said jet discharge pipes, having their longitudinal axes disposed in planes passing through the axes of said jet discharge pipes and tubes, with their forward ends disposed in communication with said combustion chambers and their rear ends formed withair collection headers extending into said jet discharge pipes at points rearwardly of said combustion chambers and adjacent the discharge ends of said funnelshaped air collection jackets, said headers being formed with inlet openings disposed rearwardly of said combustion chamber and jacket discharge ends to receive the air from said funnel-shaped jacket and a portion of the dynamic discharge from said combustion chamber and convey the same forwardly into saidicombustion chamber, valved air supplyin means in the forward portion of each combustion chamber facing forwardly,. for supplying air thereinto, adjustable fuel supply means connected to both of the combustion chambers for selectively supplying fuel alternately to'said co bustion chamv means having an air inlet port facing forwardly for moving said valved fuel supply means to sup-- ply said fuel to both of said combustion chambers simultaneously. a

7. In a dual jet propulsion engine, a pair of side-by-side jet propulsion units disposed in spaced parallel relation, each unit including an enlarged, substantially spherical combustion head having a combustion chamber therein formed with a short jet discharge nozzle in its rear face, and air and'fuel introducing means in its front face, air collecting funnel means facing forwardly and surrounding each combustion head, terminating in a jet discharge tube extending rearwardly therefrom constructed and arranged to receive air entering said air collection funnel from around said combustion head and to receive a portion of the jet discharge from said combustion chamber through the short jet discharge nozzle in the combustion head, a U-shaped conduit extending between said combustion chambers in communication with said combustion chambers, a plurality of conduits extending forwardly and rearwardly in spaced parallel relation to each other around each of said jet discharge tubes with their forward ends disposed in communication with the interior of said combustion chambers and their rear ends projecting into the interior of said jet discharge tubes and terminating in forwardly facing air collection ports disposed in substantial alignment with the discharge ends of said air collection funnels and the combustion chamber discharge nozzles, to receive air passing into and discharged from said funnel and at least a portion of the gases and the shock waves which are projected from said nozzle incident to combustion within said combustion chambers, and convey the same forwardly into said combustion chambers, means for supplying fuel under pressure to said combustion chambers comprising a fuel supply reservoir, means for delivering fuel therefrom under pressure to said combustion chamber, a valve between said fuel supply means and said fuel introducing means for each combustion chamber for selectively controlling the delivery of fuel thereto, a pressure operated actuator for actuating each of said valves to admit fuel selectively to each of said combustionchambers, said pressure operated actuator having a pressure supply conduit therefor connected to the other combustion chamber for utilizing the combustion pressure within each combustion chamber to introduce fuel into the other combustion chamber, a fuel flow regulating valve in said fuel supply, barometric pressure operated valve adjusting means connected tosaid fuel flow regulating valve for predetermined adjustments thereof incident to predetermined baro. metric pressures, and supplemental valve adjusting means comprising an air pressure oper- 14 tending forwardly to receive air pressure thereinto incident to the velocity of air passing said conduit, pressurizing said last named conduit to adjust said regulating valve.

8. In a jet propulsion engine of the class described, a plurality of jet propulsion units, each unit comprising a combustion chamber having air admission one-way valve means in one side thereof and a jet discharge port in the-Opposite side thereof with a jet reaction discharge pipe leading from said discharge port, a curved communication passage extending between said jet reaction pipes having its opposite ends disposed in communication with said jet reaction pipes in directions extending toward said combustion. chambers, to alternately receive a portion of the jet discharge from the discharge port of each combustion chamber and jet discharge pipe and convey and discharge the same into the other jet discharge pipe in a direction extending toward its associated combustion chamber, an athodyd casing surrounding each of said combustion chambers andthe jet reaction discharge pipe extending therefrom, having a restricted air admission port in its forward end, facing in the same direction as the combustion chamber air introducing valve means, said athodyd having an intermediate enlarged air expansion chamber and a rearwardly converging air discharge passage surrounding said Jet reaction discharge pipe, terminating in an air discharge port 10- cated adjacent the discharge end of the jet reaction discharge pipe, a pressure operated fuel supply means for supplying fuel to both of said combustion chambers, fuel control valve means intermediate each combustion chamber and the fuel supply means, pressure operated valve actuating means for each valve, a pressure supply conduit therefor disposed in pressure receiving communication with the combustion chamber associated with the valve actuating means for controlling fuel introduced into the other combustion chamber.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,125,157 Ostenberg Jan. 19, 1915 1,314,561 wright Sept. 2, 1919 1,983,405 Schmidt Dec. 4, 1934 2,124,462 Cummings July 19, 1938 2,432,213 Rutishauser Dec. 9, 1947 FOREIGN PATENTS Number v Country Date 176,838 Great Britain Mar. 6, 1922 515,635 Germany Jan. 8, 1931 844,442 France Apr. 24, 1939 

